2005 Volume 69 Issue 2 Pages 83-90
The longarm grenadier, Abyssicola macrochir (Günter), which dominates in a demersal fish assemblage on the upper continental slope from 200 to 500 m off the Pacific coast of northeastern Japan (Tohoku coast), was examined with respect to distribution, age composition, life cycle and feeding habits, in 1999 and 2000. A dense population of A. macrochir was observed off the southern Tohoku coast during autumn, but the population was sparse during other seasons. The population was mainly composed of 0+, 1+ and 2+ fish. GSIs lower than 1.0 were observed throughout the year, suggesting that they were at an immature stage. Major prey organisms were micronekton such as Euphausia pacifica, Sergestes similis and Diaphus theta. These observations suggest that young immature A. macrochir, subtropical demersal fish, use the upper continental slope off the southern Tohoku coast seasonally to feed on highly productive subarctic micronektons in autumn when warm water expands northward from the Kuroshio Extension to the area.
